SAN DIEGO — The man who assassinated Robert F. Kennedy 45 years ago was transferred to Donovan State Prison in Otay Mesa from a Kings County penitentiary Friday — on the 50th anniversary of the murder of the New York senator’s older brother, President John F. Kennedy.

Sirhan Sirhan, 69, arrived at the southern San Diego County prison Friday afternoon, according to the California Department of Corrections and Rehabilitation, which described the move as routine and the timing “simply an unfortunate coincidence.”

“Inmates are transferred frequently in our system,” CDCR press secretary Jeffrey Callison said.

Sirhan previously was housed at Corcoran State Prison in Central California, according to Callison.

Officials with the agency “don’t comment on the reasons” for such moves, in part because they involve security concerns, the spokesman said.

Sirhan was convicted in April 1969 of first-degree murder and assault with attempt to commit murder in connection with the June 5, 1968, assassination of Robert Kennedy, 42, at the Ambassador Hotel in Los Angeles. Five other people also were shot during the attack but survived.

The defendant initially was sentenced to death, but the punishment was commuted to life in prison after the California Supreme Court declared the death penalty law in effect at the time in 1972 as unconstitutional.

Sirhan has claimed amnesia brought on by the consumption of too much alcohol and has said he did not commit the crime.

In March 2011, he was denied parole for a 13th time.

John F. Kennedy was gunned down on Nov. 22, 1963, as he rode in a convertible limousine in Dallas with first lady Jacqueline Kennedy. His accused killer, Lee Harvey Oswald, was in turn shot to death two days later by local nightclub owner Jack Ruby.